CD38 and plasma cell myeloma: Various studies have corroborated that CD38 is expressed at different levels in various neoplastic and nonneoplastic diseases, particularly in hematological malignancies such as multiple myeloma (100% CD38+) (26), chronic lymphocytic leukemia (30-50% CD38+) (27), Waldenstrom macroglobulinemia (40% CD38+) (28), primary systemic amyloidosis (53% CD38+) (29), mantle cell lymphoma (60% CD38+) (30), T cell lymphoma (50-80% CD38+) (31), NK/T cell lymphoma (90% CD38+) (32, 33), etc.